Digital Subscriber Line (xDSL) modems provide the ability to transmit data at high rates across twisted pair telephone wiring. The electronic circuitry and frequencies required to accomplish this task can generate substantial electromagnetic (EM) radiation. Such EM radiation can be problematic because a device that exhibits high EM radiation can fail to satisfy United States Federal Communications Commission (FCC) requirements for electronic devices. Furthermore, high EM radiation can interfere with the operation of other electronic equipment.
Some conventional xDSL modems address the EM radiation problem by forming the housing for the xDSL circuitry out of a relatively thick conductive material, such as cast metal. Typically, such systems are effective in sufficiently curbing the EM radiation. However, for some applications, it is desirable to create the modem housing out of composite, plastic, or other non-conductive material. For example, such housings may be used to create light-weight, less expensive devices for the mass market. Such a composite or plastic housing is generally ineffective in preventing EM radiation.
One conventional method for blocking EM radiation is to use a metal spray coating, for example a copper spray coating, applied to the inner surface of the composite or plastic housing. Such coatings are helpful but can sometimes fail to sufficiently reduce the EM radiation. Furthermore, the metal spray coating can be a time consuming and expensive process step.